Hinode Observation of the Sun’s Polar Magnetic Field and Solar Cycle Variation
The Sun’s polar magnetic field can play important roles in several physical processes such as solar dynamos, solar coronal heating, and solar wind acceleration. The first Hinode Solar Optical Telescope observations of the polar areas revealed the existence of many patches with intrinsic field strengths of over 1 kG distributed across the entire polar region. Hinode monitoring of both polar areas revealed that the distribution of the magnetic patches consists of two different components: a polarity-imbalanced component that consists of large patches and varies with the solar cycle and a stable well-balanced components consisting of small patches. It is important to continue monitoring of the polar regions to understand the formation process of the polar field in the current solar cycle.